Approved research

Loading dose of physical activity and its association with bone mineral density and fracture risk

Lay summary

This project concerns level of physical activity, musculoskeletal health, and risk of bone fracture. The researchers for this work have developed a method for quantitative assessment of physical activity from accelerometer data. In applying this expertise to the body of Biobank data they aim to answer how level of physical activity relates to bone density and muscle mass, and how these parameters are linked to fracture risk. Derived relationships from this research can have substantial value in predicting fracture risk and formulating health guidelines. Currently there are approximately 3 million people with osteoporosis in the UK, and, of these, 250,000 will suffer fractures each year. The proposed research will help in the prevention of osteoporosis and fracture by establishing dose-response relationship between physical activity and musculoskeletal health. Loading magnitude and rate (frequency) are two crucial factors that determine bone and muscle adaptations to mechanical loading. Our method of measuring loading dose via accelerometry significantly improves assessment accuracy for loading since it is the first method to register both magnitude and frequency of loading. A customised computer program will be used to analyse the raw acceleration data obtained from the UK Biobank database. Dosage of physical activity will be calculated in relation to both intensities and frequencies of loading. We will then investigate how these loading dose parameters are related to bone mineral density (BMD) and muscle mass. We will also investigate the association between loading dose parameters and the numbers and sites of fractures. We will include participants who have both acceleration data and imaging data (BMD and muscle mass data from DEXA scan).